Considerable efforts by armament manufacturers throughout the world have been devoted to developing automated apparatus for handling ammunition for large field weapons. This is particularly so in the case of mobile direct-fire weapons carried by armored vehicles, such as tanks. Presently the tasks of withdrawing ammunition rounds or shells from magazine storage and loading them into the breech of a tank cannon are almost universally being accomplished manually. A person performing the duties of a gun loader is thus an essential member of a military tank crew. To accommodate his movement in retrieving shells from a magazine and ramming them into the cannon breech, considerable space must be allotted for these activities within the tank, more typically within the revolving gun turret of the tank. Adequate headroom should be provided so the gun loader can work standing up. Unfortunately, this increases the vertical profile of the tank and thus its size as a target to hostile fire. The turret must, therefore, be heavily armored to maximize tank and crew survivability against enemy fire. Of course, heavy armor plating adds tremendously to the weight of a tank, which then requires a larger power pack, drive train, and suspension.
The factors of greater overall profile and the consequences thereof, the elimination of a gun loader and the consequent space savings, and the prospect of higher firing rates have heretofore been the primary motivations for developing a satisfactory autoloader for tank cannons. New tank designs calling for an overhead cannon mounted exteriorly to the roof of a turret that is essentially flush with the deck of a tank have rendered autoloading a virtual necessity.
Of the numerous autoloaders seen in the prior art, most are highly complex, extraordinarily space-consuming, difficult to maintain and susceptible to frequent malfunction. Many of the existing designs require that the cannon return to a predetermined position, particularly in elevation, before automated loading can be effected. Thus, the cannon must be repeatedly removed from the target for reloading and returned for firing, a significant detriment to firing rate. Additionally, prior art autoloaders are powered by hydromechanical or electrohydraulic units which depend on the use of high pressure hydraulics. Thus, crew survivability may be compromised by the presence of highly flamable hydraulic fluid.